Tulip fire

The leaves and petals of my tulips are shot through with little holes. Is this some kind of insect or a disease? And what can I do to solve the problem?

Your tulips may have a fungal disease called Botrytis. According to Cornell University’s Plant Disease Diagnostic Clinic, Botrytis tulipae is specific to tulips and lilies. A more colorful name for this disease is ‘tulip fire.’ Cool and damp spring or summer conditions favor the development of the disease:
“Tulip fire infections cause malformations and/or large, light tan patches on tulip leaves. These patches are most noticeable on light-colored varieties. On leaves these infections are somewhat sunken, yellow to light tan, and surrounded by a water-soaked area.
On colored petals the spots appear white and on white petals they appear brown.”

Since the fungus can overwinter in plant debris, good garden hygiene may help:

Clean up any diseased leaves and petals, but not when they are wet.
Make sure you don’t water your tulips from above (of course, you can’t stop the rain–just don’t aid and abet it).
Avoid congested plantings–provide air circulation around your plants.
Ultimately, you may want to dispose of infected plants (don’t compost).
Rumor has it that using a grit mulch around your tulips can be helpful as a preventive measure.

The Royal Horticultural Society advises that gardeners not plant tulips in a location where Botrytis has been present for three years. According to University of Illinois Integrated Pest Management, there is no point using fungicide where the fungus is already present, but they do describe preventive uses. Always look for the least toxic option. There are some Neem-based fungicides available for home gardeners.

An article in the Telegraph by garden writer Sarah Raven gives an excellent overview of the problem and how to manage it. She highly recommends not hesitating to remove infected plants and bulbs at first discovery, the better to keep the disease from spreading. Early tulips are less susceptible, and according to Raven, the most susceptible in her garden are Darwin tulips, while Viridiflora hybrids are unaffected. Avoid cross-contaminating lilies, fritillaries, and Juno irises by planting them at a distance from your tulips.

Fungal diseases of plants, Tulipa

bulb care after bloom

Bulbs in pots – when to plant?

Daffodils & tulips wilting in pots now, what to do with them? Can you put them in the ground right now, or should you wait till fall? Keep them dry, wet, what?

Yes, you can put them in the ground right now or you can lift them, keep them dry and plant them in the fall. Growing in pots is stressful to bulbs, so you may find fewer flowers next year.

Most tulips do not flower reliably each year, even if they were grown in the ground, so many people treat them as annuals (dig up and toss!) BUT some tulips do re-flower (Darwin Hybrids, Fosterianas and species tulips) so if you are not sure what you have, go ahead and replant. Both tulips and daffodils dislike summer water, so make sure you either plant them in a place where they will stay dry or make sure they are planted in really well-drained soil. Mixing gravel into the soil can help with drainage.

planting over tulips and when to fertilize tulips

I have planted petunias over tulip bulbs. Is that o.k., and also, how and when can I fertilize tulips this fall?

Your idea of planting a later blooming plant over the tulips is just fine. It will conceal the dying foliage nicely. According to The Plant Care Manual by Stefan Buczacki (Crown,1993), the time to fertilize tulips–if you need to fertilize them at all–is early spring. They can be mulched (with compost, for example) in early fall and spring, and given liquid feed 2-3 times after blooming and while still in full leaf.

The Brooklyn Botanic Garden’s Spring-Blooming Bulbs (2002) gives the following general advice:
“Most bulbs do better with regular fertilizing, and bulb fertilizer is one good choice. Some gardeners prefer to use bone meal (though the way it is processed today saps most of its nutrients) or rock phosphate. Even better is a healthy dose of compost–in fact, if you regularly improve the overall quality of your soil with compost and other organic amendments, you don’t have to provide much fertilizer for most bulbs. Mix compost or fertilizer into the soil when you’re planting or top-dress, following label directions. to help boost the bulbs for next year’s bloom, you can also top-dress the soil in spring after blooming. Remember to work any fertilizers well into the soil, and avoid high-nitrogen fertilizers (like lawn fertilizer).”

You may not need to fertilize your tulips if they are the showy varieties (the ones that don’t come back year after year in the garden). Seattle-area gardening expert Ciscoe Morris says the following:
“Don’t fertilize spring-blooming bulbs if you’re going to replace them next fall. Most books recommend adding bone meal and fertilizer whenever you plant spring-blooming bulbs. That’s only necessary if the bulbs you’re planting are the kind that tend to naturalize and return to bloom every spring for years to come. Those bulbs not only need fertilizing at planting time, but also should be fed every spring thereafter. On the other hand, most of the big, showy tulips are ill-suited for our rainy cold winters and rarely perform well the second year. If, like most of us, you treat them as annuals and replace the bulbs every year, don’t waste time and money fertilizing them. These bulbs already contain everything they need to grow and bloom, and as long as the bulbs don’t rot as the result of poor drainage, and nothing eats them, they’ll put on a great display without the addition of nutrients.”

on pruning flowering bulbs

This is my first year planting spring flowering bulbs, which
grew nicely. I cut the dead flower and the stalk once it died back, and now the
foliage is yellow. What am I supposed to do with the yellow foliage? Pull it out? Cut it off? Just leave it alone? Also, will
planting some annual petunias now hurt the bulbs I have planted in the
garden? How close can I plant the petunia to the bulbs? I was going to
try and hide the yellow foliage.

The answer will depend on which bulbs you were growing. For example,
daffodil stems should not be cut back until at least 6 weeks after the
flowers have faded, and you should never tie the foliage in knots or
braid it (this is a common but ill-advised habit). You can leave
daffodils in the ground to naturalize and spread.

With tulips, you also need to wait at least 6 weeks from the fading of
the flowers before cutting back the leaves.

With hyacinths, you can pull away dead foliage and flower stems as they
fade. When the top growth has died down, you can either leave them in the
ground or dig up the bulbs, dry them off, and store them for replanting.

If you are growing iris, you can cut the dead flower stems to the base,
and cut away dead leaves in the summer. If they are bearded iris, the
fan of leaves may be cut back in the fall to about 8 inches above the
base.

(Source: The Plant Care Manual by Stefan Buczacki, Crown Publishers,
1993)

You can certainly plant your annual petunias quite close to bulbs like
daffodils and tulips and other bulbous plants which are quite vertical.
Just don’t plant right on top of the bulbs. To disguise dying bulb foliage, use perennial ground cover plants that keep their leaves over the winter, and that have stems soft enough for bulbs to emerge through them. Hardy geraniums (true geraniums, also called cranesbill) and creeping veronica, such as Veronica peduncularis ‘Georgia Blue,’ are good choices. You can remove dried leaves as needed, and they can be tidied or groomed in early spring.

on planting Darwin tulips

Will my Darwin hybrid tulips come back every year?

In his book Ask Ciscoe (Sasquatch Books, 2007), local garden expert Ciscoe Morris suggests planting Darwin and Empress hybrid tulips 12 inches deep (rather than the often recommended 6 inches) so that the bulbs will be less likely to divide and the squirrels less likely to dig them up.

Ann Lovejoy says much the same thing…plant tulips 10 inches deep, in a sunny spot, and in well-drained soil, and some are likely to return for several years. (See Seasonal Bulbs, 1995, p.16)

Skagit Valley Tulip Festival

Garden Tip #64

What to do with a flower bulb once the flower is gone? It depends! For daffodils, remove the seed head, but let all the foliage turn yellow before you remove it. Braiding the foliage is not recommended because the toxins in the leaves can cause contact dermatitis. If a clump is getting crowded dig and separate the bulbs once the leaves have started to wither. Thin out the small and damaged bulbs and replant the rest. Or store the bulbs, unwashed, in a dry shaded place until September.

For tulips, it’s a bit more complex. Most showy, large-flowered tulips don’t rebloom well, so should be treated like an annual- dug up and tossed. However, Darwin Hybrids, ‘Apeldoorn’ is one example, do rebloom the following year. These should be allowed to yellow and wither naturally and their seed heads removed. They can be divided when the foliage withers. If you don’t know what you have, play it safe and leave your tulips for another year. If the show is disappointing then dig them up and toss.

For a fun tour of the world of bulbs try Lois Hole’s Favorite Bulbs (Hole’s, $1995), a book packed with photos, trivia, growing advice and design tips.

Asters, chrysanthemum, salvias and ornamental grasses are a few perennials that emerge and distract the eye when bulb foliage is yellowing.